Synthesis of glycophospholipid and peptide-phospholipid conjugates and uses thereof

Abstract

The present invention provides glycophospholipid and peptide-phospholipid conjugates comprising a phospholipid moiety and a saccharide or peptide moiety joined by an ether linkage comprising a secondary or tertiary amine. The conjugate structure of the invention comprises a flexible spacer arm between the phospholipid and saccharide or peptide moieties which, being variable in length, serves to optimize saccharide or peptide bioactivity. This invention further provides a method for the synthesis of such conjugates comprising the step of reductive amination. The method is efficient, economical and provides a high yield of product. Glycophospholipid and peptide-phospholipid conjugates of the invention can be incorporated and, optionally, chemically polymerized in self-assembling systems such as membranes, bilayers, films, liposomes and the like, and find utility diagnostically and therapeutically in medical and immuno-biological applications.

We claim:  
     
       1. A self-assembling system comprising a glycophospholipid or a peptide-phospholipid conjugate, having a phospholipid moiety and a saccharide or peptide moiety joined by a diether linkage comprising a secondary or tertiary amine, said conjugate having the formula                    
       wherein 
       R 1  and R 2  are independently selected from the group comprising straight or branched, unsubstituted or substituted, saturated or unsaturated acyl, alkyl, alkenyl, alkynyl and aryl groups;  
       Y is a cation;  
       X is a secondary or tertiary amine linker, comprising two to twenty carbon atoms, wherein a substituent group of the amine is selected independently from a group comprising a hydrogen, a straight or branched, unsubstituted or substituted alkyl, alkenyl, alkynyl and aryl groups; and  
       Z is a saccharide, a peptide or a functionalized derivative thereof; and a member selected from the group consisting of a membrane, a bilayer, a film, a liposome and a carrier-vehicle.  
     
     
       2. The self-assembling system of claim  1  wherein said which is a substrate for medical implants or for growing cells and/or organs. 
     
     
       3. A liposome comprising a glycophospholipid or a peptide-phospholipid conjugate, having a phospholipid moiety and a saccharide or peptide moiety joined by a diether linkage comprising a secondary or tertiary amine, said conjugate having the formula                    
       wherein 
       R 1  and R 2  are independently selected from the group comprising straight or branched, unsubstituted or substituted, saturated or unsaturated acyl, alkyl, alkenyl, alkynyl and aryl groups;  
       Y is a cation;  
       X is a secondary or tertiary amine linker, comprising two to twenty carbon atoms, wherein a substituent group of the amine is selected independently from a group comprising a hydrogen, a straight or branched, unsubstituted or substituted alkyl, alkenyl, alkynyl and aryl groups; and  
       Z is a saccharide, a peptide or a functionalized derivative thereof.  
     
     
       4. The liposome of claim  3  further comprising a drug or therapeutic agent. 
     
     
       5. The liposome of claim  3  wherein said drug or therapeutic agent is selected from the group comprising, an antibiotic, a chemotherapeutic agent and an anti-inflammatory agent. 
     
     
       6. The liposome of claim  4  wherein said drug or therapeutic agent is a diagnostic. 
     
     
       7. The liposome of claim  3  which is specific for a designated cell or tissue. 
     
     
       8. The liposome of claim  4  wherein said drug or therapeutic agent is a protein or a DNA. 
     
     
       9. The liposome of claim  8  wherein said protein is a monoclonal antibody. 
     
     
       10. A pharmaceutical composition comprising the liposome of claim  4  and a pharmaceutically acceptable carrier. 
     
     
       11. A method for producing a glycophospholipid or peptide-phospholipid conjugate having a phospholipid moiety and a saccharide or peptide moiety joined by a diether linkage comprising a secondary or tertiary amine, said conjugate having the formula                    
       wherein 
       R 1  and R 2  are independently selected from the group comprising straight or branched, unsubstituted or substituted, saturated or unsaturated acyl, alkyl, alkenyl, alkynyl and aryl groups;  
       Y is a cation;  
       X is a secondary or tertiary amine linker, comprising two to twenty carbon atoms, wherein a substituent group of the amine is selected independently from a group comprising a hydrogen, a straight or branched, unsubstituted or substituted alkyl, alkenyl, alkynyl and aryl groups; and  
       Z is a saccharide, a peptide or a functionalized derivative thereof; said method comprising the step of combining a phospholipid nitrogenous base with an aldehyde-functionalized saccharide or peptide derivative under conditions sufficient to form said glycophospholipid or peptide-phospholipid conjugate.  
     
     
       12. The method of claim  11  further comprising a reducing agent. 
     
     
       13. The method of claim  12  wherein said reducing agent is sodium cyanoborohydride. 
     
     
       14. The method of claim  11  wherein said phospholipid nitrogenous base, naturally occurring or synthetic, contains a free —NH— group. 
     
     
       15. The method of claim  11  wherein said phospholipid nitrogenous base comprises from two to eighteen carbon atoms. 
     
     
       16. The method of claim  11  wherein said phospholipid nitrogenous base is phosphatidylethanolamine. 
     
     
       17. The method of claim  11  wherein said aldehyde-functionalized saccharide or peptide derivative has the formula 
       
         
           Z—O—(CH 2 ) n−1 —CHO or Z—(OCH 2 CH 2 ) m−1 —CHO  
         
       
       wherein n=1-18, m=3-250, and Z=a saccharide, peptide or a functionalized derivative thereof. 
     
     
       18. The method of claim  11  wherein said saccharide is selected from the group consisting of a monosaccharide, a disaccharide, an oligosaccharide and a polysaccharide or is selected from the group consisting of a nucleoside, a nucleotide, polynucleotide, a DNA and an RNA. 
     
     
       19. The method of claim  11  further comprising the earlier steps of: 
       reacting an activated saccharide or peptide derivative with a diol, and  
       transforming the resultant primary hydroxyl group to said aldehyde-functionalized saccharide or peptide derivative.  
     
     
       20. The method of claim  19  wherein said diol has the general formula 
       
         
           HO(CH 2 ) n OH or H—(OCH 2 CH 2 ) m —OH  
         
       
       wherein n=1-18 and m=3-250.